* NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
*
* NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is longer than
* NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
*
* NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is longer than